Efficient magnesium lactate production with in situ product removal by crystallization

•The ISPR process is based upon magnesium lactate crystallization.•No external seed crystals are needed in crystallization.•The crystallization is conducted at 42 °C without cooling and re-heating.•Using ISPR fermentation saves 40% water, 41% inorganic salts and 43% yeast extract.

In this paper, attempts were made to develop an in situ product removal process for magnesium lactate production based on crystallization. The crystallization was conducted at 42 °C without seed crystal addition. The product concentration, productivity and yield of fermentation coupled with in situ product removal (ISPR) reached 143 g L−1, 2.41 g L−1 h−1 and 94.3%. In four cycles of crystallization, the average reuse rate of fermentation medium and removal rate of product reached 64.0% and 77.7%. At the same time, ISPR fermentation saved 40% water, 41% inorganic salts and 43% yeast extract (YE) as compared to fed-batch fermentation. The process introduces an effective way to reduce the amount of waste water and the raw material cost in magnesium lactate fermentation.